Abstract

SUMMARY:

This study reports on oral treatment with different doses of vitamin D3 ranging from 25 to 200 microg in females with 25-hydroxyvitamin D3 levels < 60 nmol/L screened for participation in an osteoporosis trial. A guidance to safely and efficiently achieve 25-hydroxyvitamin D3 levels > 60 nmol/L is presented.

INTRODUCTION:

The importance of vitamin D for skeletal health has been implemented in clinical trials in osteoporosis. The threshold of 25-hydroxyvitamin D for inclusion has changed from 30 to 60 nmol/L. This study reports on oral treatment with different doses of vitamin D3 in females with 25-hydroxyvitamin D3 levels < 60 nmol/L.

METHODS:

In 131 postmenopausal females screened for participation in an osteoporosis trial, the 25-hydroxyvitamin D3 concentration was < 60 nmol/L. They were treated with 25 (n = 22), 50 (n = 19), 75 (n = 19), 100 (n = 41) or 200 microg (n = 30) of vitamin D3 daily for at least 10 days.

RESULTS:

In the females treated with 25, 50, 75, 100 and 200 microg of vitamin D3 daily the 25-hydroxyvitamin D3 concentrations increased significantly from 32.4 +/- 2.7 (mean +/- SEM) to 50.8 +/- 2.9, from 46.7 +/- 2.8 to 65.8 +/- 2.6, from 41.6 +/- 2.7 to 67.4 +/- 2.9, from 46.7 +/- 1.4 to 64.4 +/- 2.2 and from 42.1 +/- 2.0 to 71.2 +/- 2.8 nmol/L, respectively (p < 0.001). S-calcium increased significantly but within the reference range (p < 0.006).

CONCLUSION:

Oral vitamin D3 safely increased 25-hydroxyvitamin D3 concentrations in all females above 60 nmol/L. This study demonstrates how to achieve the new recommended 25-hydroxyvitamin D concentrations within the screening period of a clinical trial.